The present invention relates to a key telephone system, and more particularly, to a key telephone system in which a handset can be regulated.
A handset is provided with a terminal of a telephone set in a key telephone system, which is transmitting and receiving speech signals from an office line or other telephone terminals. As shown in FIG. 1, the speech signals which are supplied to the handset are set to a fixed default value as a reference. In a conventional key telephone system, when volume received by the handset is small or high, a user regulates the volume to a desired value. This regulated volume automatically returns to the fixed default value when the handset is put on a housing and becomes in a telephone call condition again.
Therefore, the conventional telephone system has the problem that the manipulation is complicated because it is necessary for the user to regulate volume again when the user talks over the telephone by using the handset.
Furthermore, since the conventional system sets to the fixed default value, this system has the problem that the predetermined volume is not only unsuitable for the user but also hard to hear because the volume is too much or little.